[PATCH] Input: fix add modalias support build error

Fix build when scripts/mod/file2alias.c includes linux/input.h, which
tries to include /usr/include/linux/mod_devicetable.h:

 In file included from scripts/mod/file2alias.c:40:
 include/linux/input.h:21:35: linux/mod_devicetable.h: No such file or directory
 make[2]: *** [scripts/mod/file2alias.o] Error 1

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>